After circling the bases on his fifth-inning two-run homer, the A’s Yoenis Cespedes stuck out his two index fingers, pointed them at the crowd behind the third base dugout and alternately waggled them up and down.

This series, for the first time, Cespedes had his mother in the stands. She and some other family members had been in St. Petersburg for a series with the Rays late last month, but Cespedes was hurt and didn’t play in the series.

So this weekend was important to mother and son. Cespedes, talking through interpreter Ariel Prieto, said his mother, sitting in a sea of his cousins, stuck out her index fingers and waggled right back.

“She hadn’t seen me play since I’d been in the Dominican Republic,’’ the Cuban-born Cespedes said in explaining the importance of the moment.’’

Cespedes homer gave the A’s a 4-1 lead at the time and it was one of those moments in the game without which Oakland would not have won.

The long ball came off Andy Pettitte, the veteran left-hander against whom Cespedes said he’d faced many times “while watching him on TV.’’

“I rushed the first two at-bats a little,’’ he said. “The third at-bat, I tried to go to the batter’s box with more patience. The first at-bats I saw mostly pitches outside. The difference the third time was the pitch was inside.’’

The A’s were struggling when Cespedes was on the disabled list, but they are 5-2 since his return. He’s 9-for-31 (.290) with eight runs scored and nine RBIs in those seven games. Oakland is 13-4 when he’s in the lineup this year, 5-10 when he’s not and 95-50 when he’s started since joining the team in 2012.

“He makes everybody better,’’ manager Bob Melvin said. “No one else has to bat cleanup. The other hitters are more apt to pass the baton. It’s important.’’

–Josh Donaldson had 11 plate trips before stepping into the batter’s box in the eighth inning in Yankee Stadium Sunday.

Those at-bats taught him to expect to see a fastball from lefty reliever Boone Logan.

“The entire series their staff was throwing me fastballs,’’ Donaldson said. “I’ve faced Boone before and I know he has a good one. I was looking for one.’’

He got one and parked it in the second deck for the game-winning blow.

“They’d been throwing me away, away,’’ Donaldson said. “This one was more on the plate. He definitely didn’t hit his spot.’’

Donaldson hit his, though.

–Luke Montz said when he was called up Wednesday that he didn’t know after being up with the Washington Nationals in 2008 if he’d ever make it back to the big leagues.

He felt much the same way about hitting another big league homer. He’d hit one for Washington back then, and then never again. Until the fourth inning Sunday, that is, when he took Andy Pettitte out of the park on a 3-2 pitch, breaking a 1-all tie.

“It felt like hitting the first one,’’ Montz said. “And to do it in Yankee Stadium against Andy Pettitte made it all that much more special.’’

Montz has played in three games and is 3-for 11, two doubles and the homer. It’s more of a contribution that he might have expected to make when he was sent down at the end of spring training.

“But BoMel (manager Bob Melvin) sat me down and said `go down and get off to a hot start,’ ’’ Montz said. “He said `Things happen here.’ ’’

True enough. The A’s got two outfielders, Coco Crisp and Chris Young, hurt last Monday in a 19-inning win over the Angels. So they called up Montz, who’s a catcher and DH. Go figure.

“I never thought it would be me,’’ Montz said. “I’m happy to have the chance to come here and contribute.’’

–The A’s had hoped shortstop Hiro Nakajima would be in the lineup Sunday for Triple-A Sacramento.

But he felt some pain in his troublesome hamstring after playing for the River Cats on Friday, and he wasn’t able to play Sunday.

As a result, he’s expected to be checked out again by the A’s doctors Monday in Oakland.

–Dan Straily said the difference between Sunday’s strong start against the Yankees and last Monday’s so-so start against the Angels was his attitude.

“I felt like I was the attacker and not the attacked,’’ Straily said after pitching 5.1 innings and giving up three runs. He left with a 4-1 lead, but the usually reliable Jerry Blevins had a rough go of it as he let two inherited runners score and let the lead slip away.

Straily wasn’t complaining.

“I made some pitches that were better quality,’’ he said. “It was a good thing that I just relaxed and trusted Dino (catcher Derek Norris).’’

–Speaking of Norris, he took a wild pitch off his left wrist in the ninth inning, a pitch that moved the tying run into scoring position. He was checked out by the medics, but he was not coming out of the game.

“It’s sort of like being hit on your funny bone,’’ Norris said. “It went dead for a bit. But it was OK.’’

–Josh Reddick came into Yankee Stadium this weekend hitless in 27 at-bats in the Bronx. That streak stretched to 33 before his ninth-inning double after coming in as a defense change.

“I’m 1-for-34 now,” Reddick said. “Now I’ve got an average.”

It’s worth of note that Reddick’s double came against a left-hander. And not just any left-hander but Boone Logan, against whom Reddick had never gotten a hit.